Electrolytic solution, secondary battery and electric device

Abstract

An electrolytic solution, a secondary battery and an electric device are described. The components of the electrolyte comprise a functional compound represented by formula (1). In formula (1), T 1 -T 3 are each independently selected from any one of an alkyl group having 1-10 carbon atoms, an alkenyl group having 2-10 carbon atoms, an alkynyl group having 2-10 carbon atoms, and groups represented by following formulae (a)-(f). Among T 1 -T 3 , at least one is selected from the group represented by formula (a), and at least one is selected from the group represented by formula (b), (c), (d) or (e). In a charging/discharging process of the electrolyte, the functional compound represented by formula (1) can capture an oxidation product and improve the toughness of a formed SEI film, thereby improving the cycle performance of a secondary battery.

What is claimed is: 
     
         1 . An electrolytic solution, wherein components of the electrolytic solution comprise a functional compound represented by formula (1): 
       
         
           
           
               
               
           
         
         wherein T 1 -T 3  are each independently selected from any one of alkyl with 1-10 carbon atoms, alkenyl with 2-10 carbon atoms, alkynyl with 2-10 carbon atoms, and groups represented by following formulas (a)-(f); among T 1 -T 3 , at least one is selected from the group represented by formula (a), and at least one is selected from the group represented by formula (b), (c), (d), or (e); 
       
       
         
           
           
               
               
           
         
         wherein R 1 -R 3  are each independently selected from any one of H, substituted or unsubstituted alkyl with 1-5 carbon atoms, substituted or unsubstituted alkenyl with 2-5 carbon atoms, substituted or unsubstituted alkynyl with 2-5 carbon atoms, and aryl with 6-15 ring atoms, at least one R 1  is not H, and at least one R 2  is not H; 
         R 4 -R 6  are each independently selected from a single bond, substituted or unsubstituted alkylene with 1-5 carbon atoms, or substituted or unsubstituted alkenylene with 2-5 carbon atoms; 
         L 1  is selected from a single bond or NR 7 , R 7  is selected from any one of H, substituted or unsubstituted alkyl with 1-5 carbon atoms, substituted or unsubstituted alkenyl with 2-5 carbon atoms, substituted or unsubstituted alkynyl with 2-5 carbon atoms, aryl with 6-15 ring atoms, and 
       
       
         
           
           
               
               
           
         
       
       and L 2  is selected from a single bond or alkylene with 1-5 carbon atoms;
 X 1  is C(R 8 ) 2 , and X 2  is C(R 9 ) 2 ; each R 8  and each R 9  are each independently selected from any one of H, substituted or unsubstituted alkyl with 1-5 carbon atoms, substituted or unsubstituted alkenyl with 2-5 carbon atoms, and substituted or unsubstituted alkynyl with 2-5 carbon atoms; 
 * denotes an attachment site. 
 
     
     
         2 . The electrolytic solution according to  claim 1 , wherein the functional compound comprises a nitrogen atom. 
     
     
         3 . The electrolytic solution according to  claim 1 , wherein the functional compound comprises at least one of 
       
         
           
           
               
               
           
         
       
       and the group represented by formula (c). 
     
     
         4 . The electrolytic solution according to  claim 1 , wherein R 1 -R 3  are each independently selected from any one of H, alkyl with 1-5 carbon atoms, halogen-substituted alkyl with 1-5 carbon atoms, alkenyl with 2-5 carbon atoms, halogen-substituted alkenyl with 2-5 carbon atoms, alkynyl with 2-5 carbon atoms, and halogen-substituted alkynyl with 2-5 carbon atoms;
 optionally, R 1 -R 3  are each independently selected from any one of H, alkyl with 1-3 carbon atoms, halogen-substituted alkyl with 1-3 carbon atoms, alkenyl with 2-3 carbon atoms, halogen-substituted alkenyl with 2-3 carbon atoms, alkynyl with 2-3 carbon atoms, and halogen-substituted alkynyl with 2-3 carbon atoms.   
     
     
         5 . The electrolytic solution according to  claim 1 , wherein R 4 -R 6  are each independently selected from any one of a single bond, alkylene with 1-5 carbon atoms, halogen-substituted alkylene with 1-5 carbon atoms, alkenylene with 2-5 carbon atoms, and halogen-substituted alkenylene with 2-5 carbon atoms;
 optionally, R 4 -R 6  are each independently selected from any one of a single bond, alkylene with 1-3 carbon atoms, halogen-substituted alkylene with 1-3 carbon atoms, alkenylene with 2-3 carbon atoms, and halogen-substituted alkenylene with 2-3 carbon atoms.   
     
     
         6 . The electrolytic solution according to  claim 1 , wherein R 7  is selected from any one of alkyl with 1-5 carbon atoms, halogen-substituted alkyl with 1-5 carbon atoms, and 
       
         
           
           
               
               
           
         
         optionally, R 7  is selected from any one of alkyl with 1-3 carbon atoms, halogen-substituted alkyl with 1-3 carbon atoms, and 
       
       
         
           
           
               
               
           
         
       
     
     
         7 . The electrolytic solution according to  claim 1 , wherein each R 8  and each R 9  are each independently selected from any one of H, alkyl with 1-5 carbon atoms, halogen-substituted alkyl with 1-5 carbon atoms, alkenyl with 2-5 carbon atoms, and halogen-substituted alkenyl with 2-5 carbon atoms;
 optionally, each R 8  and each R 9  are each independently selected from any one of H, alkyl with 1-3 carbon atoms, halogen-substituted alkyl with 1-3 carbon atoms, alkenyl with 2-3 carbon atoms, and halogen-substituted alkenyl with 2-3 carbon atoms.   
     
     
         8 . The electrolytic solution according to  claim 1 , wherein the functional compound comprises at least one of the following (I)-(X): 
       
         
           
           
               
               
           
         
       
     
     
         9 . The electrolytic solution according to  claim 1 , wherein the components of the electrolytic solution further comprise an electrolyte salt and an organic solvent;
 based on a total volume of components in the electrolytic solution excluding the electrolyte salt and the functional compound, a concentration A of the functional compound satisfies: A≥0.05 mol/L;   
       
         
           
             
               optionally 
               , 
               
                 
                   
                     0.05 
                         
                     mol 
                     / 
                     L 
                   
                   ≤ 
                   A 
                   ≤ 
                   
                     1 
                     ⁢ 
                         
                     mol 
                     / 
                     L 
                   
                 
                 ; 
               
             
           
         
         
           
             
               
                 further 
                 ⁢ 
                     
                 optionally 
               
               
                 , 
               
               
                 
                   
                     0.25 
                   
                   
                         
                   
                   mol 
                   / 
                   L 
                 
                 ≤ 
                 A 
                 ≤ 
                 
                   0.75 
                        
                   mol 
                   / 
                   
                     L 
                     . 
                   
                 
               
             
           
         
       
     
     
         10 . The electrolytic solution according to  claim 9 , wherein the components of the electrolytic solution further comprise a film-forming agent. 
     
     
         11 . The electrolytic solution according to  claim 10 , wherein a volume ratio of the film-forming agent to the organic solvent is 1:(0.5-3);
 optionally, a volume ratio of the film-forming agent to the organic solvent is 1:(1-3).   
     
     
         12 . The electrolytic solution according to  claim 9 , wherein the electrolyte salt comprises a first electrolyte salt and a second electrolyte salt;
 the first electrolyte salt comprises at least one of lithium bis(fluorosulfonyl) imide and lithium hexafluorophosphate;   the second electrolyte salt comprises at least one of lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium difluorobis(oxalato)phosphate, lithium tetrafluoro(oxalato)phosphate, and lithium difluorophosphate.   
     
     
         13 . The electrolytic solution according to  claim 12 , wherein the electrolyte salt satisfies at least one of the following conditions (1)-(2):
 (1) based on a total volume of components in the electrolytic solution excluding the electrolyte salt and the functional compound, a concentration of the first electrolyte salt is 0.5 mol/L to 4 mol/L; and   (2) based on a total volume of components in the electrolytic solution excluding the electrolyte salt and the functional compound, in the electrolytic solution, a concentration of the second electrolyte salt is 0.05 mol/L to 1.5 mol/L.   
     
     
         14 . The electrolytic solution according to  claim 12 , wherein the concentration of the first electrolyte salt is greater than the concentration of the second electrolyte salt. 
     
     
         15 . A secondary battery, comprising the electrolytic solution according to  claim 1 . 
     
     
         16 . An electric device, comprising the secondary battery according to  claim 15 .